Pipes and other tubulars have been lined with polymeric liners (e.g. polyethylene, nylon 11, etc.) for many years and several installation techniques are known to the art. These systems have been used principally in offshore and onshore pipelines, and in downhole production tubulars. Their scope has generally been limited to corrosion and erosion protection. However, they have also been used in monitoring for integrity of the composite liner-host system, as disclosed in U.S. Pat. No. 5,072,622 (Roach and Whitehead)
Generally, the liner resides in close-tolerance with the host pipe along its length, forming a stable composite system, as shown in FIG. 1 which is a cutaway end view of a tubular 10 lined with a liner 11. The installed liner may be either of a loose-fit or a compressed-fit variety, both well known to the art. In all but low pressure applications, the stresses induced by fluid pressure from within the liner are transmitted to the surrounding xe2x80x9chostxe2x80x9d tubular, and resisted by same. The liner acts as an intermediary layer.
The invention described herein expands the range of possible applications of liners by providing for manipulation and control of annular fluids within the lined tubular systems.
The disclosed embodiments of the invention provide, among other features, a continuous annulus along the length of plastic-lined tubular, and if applicable, through any intermediary joints.